If it is an oil painting you are plumb out of luck. Unlike watercolor and acrylic paint which dry as the water in them evaporate (and thus can be encouraged with a blow drier or a fan or some sunlight), oil paints have a siccative quality. That's a fancy way of saying that they absorb oxygen from the air which then reacts with the ingredients to harden. In other words, it is a chemical reaction.
my very unkept palette of mixed oil paint
in the silver cannister is turpenoid, a turpetine substitute for cleaning brushes
Oil paints do not have water in them. The oxygen gets absorbed through the paint's surface which means that the top surface dries first. If I leave a blob of paint on the palette for several days I come back to a tough skin across the top; if I break through that skin the inside is still fairly soft and pliable. This dying process never really stops and for textured work (guilty) it can take months to complete. In fact, artists are well advised not to varnish a painting until at least 6 months after completion to be certain it is completely dry...otherwise cracks will appear from the varnish drying on top of wet paint.
while I know the fan won't speed the drying it makes me feel better,
like I am helping in some way
And to make matters even more chemically complicated, certain colors (pigments) take longer to oxidize than others, and not all "whites" or all "reds" fall into the same (slow, longer, longest) categories. I went online looking for some magic words to speed the drying time and learned that some folks put the piece under a light bulb or in the warm sun. I'm not sure I understood the reasoning but I do know that setting up a fan makes me feel better.
And there is another funny chemical application. Oil paints are not cheap; some small tubes cost $29.95 and up. So when extra paint is on your palette and you are closing up shop it really hurts to trash that cash. I have covered mine before in a tupperware-like container and placed it in the freezer. Works fine to protect the paint for about a week or so. But I read where others submerged their palette under water. Now that makes chemical sense but sure sounds like a mess to me.
Anyway, chemistry was never my long suit although I was told by my college professor (as he threatened to fail me) that I would need it someday in my "real life." I really hate to admit he might have been correct.
If you are local I hope you'll stop by the ArtWorks Festival in downtown Eau Gallie. See you there.